WO2007097235A1

WO2007097235A1 - Process for production of fuel base

Info

Publication number: WO2007097235A1
Application number: PCT/JP2007/052638
Authority: WO
Inventors: Yuichi Tanaka; Shinya Takahashi; Yoshifumi Chiba
Original assignee: Nippon Oil Corporation
Priority date: 2006-02-21
Filing date: 2007-02-14
Publication date: 2007-08-30
Also published as: MY144185A; JP2007224091A; JP4711849B2

Abstract

A process for hydrocracking wax which comprises hydrocracking a raw material wax and subjecting an uncracked wax fraction formed by the hydrocracking to hydrocracking again, characterized in that a mixture of the raw material wax and the uncracked wax fraction is hydrocracked in the presence of a hydrocracking catalyst in such a way that the conversion of the wax fraction having a boiling point of 360°C or above into a light oil fraction having a boiling point lower than 360°C falls within the range of 50 to 85% by mass. In hydrocracking uncracked wax by a bottom recycling method, the process simultaneously attains enhancement in the yield of objective middle cuts and reduction in the content of n-paraffins in middle cuts.

Description

Specification

Manufacturing method of fuel substrate

Technical field

[0001] The present invention relates to a method for producing a fuel substrate, and more particularly to a method for producing a fuel substrate from a heavy fraction.

Background art

[0002] In recent years, from the viewpoint of reducing the environmental burden, there has been a demand for an environmentally friendly clean liquid fuel with a low content of sulfur and aromatic hydrocarbons. In the oil industry, the use of Fitzia Tropsch synthetic oil (hereinafter referred to as “FT synthetic oil”) synthesized from synthesis gas containing hydrogen and carbon monoxide as a clean liquid fuel is being considered. . Since FT synthetic oil does not substantially contain environmentally hazardous substances such as sulfur and aromatic hydrocarbons, its expectations are very high.

[0003] By fractional distillation of FT synthetic oil, a middle fraction containing saturated hydrocarbons having a boiling point in the range of 150 to 360 ° C is obtained. The middle distillate of FT synthetic oil is expected to be used as a fuel base material for light oil and jet fuel. However, the fuel base material mainly composed of the middle distillate of FT synthetic oil has different characteristics such as combustion characteristics and low-temperature fluidity from conventional light oil and jet fuel. It has been pointed out that it is necessary to improve these characteristics in order to use this product in Japan.

[0004] By the way, as a method for producing a middle distillate usable as a fuel base material from FT synthetic oil, in addition to the above-described method for fractionating FT synthetic oil, a heavy fraction of FT synthetic oil is used. A method of hydrocracking and fractionating middle distillates from cracked products is known. For example, Patent Document 1 describes a method for producing a middle distillate by using a heavy fraction of FT synthetic oil as a raw material and having a high isoparaffin content by hydrocracking.

Patent Document 1: International Publication No. 00/20535 Pamphlet

Disclosure of the invention

Problems to be solved by the invention

[0005] In the method of Patent Document 1, the heavy fraction of FT synthetic oil is hydrocracked to contain isoparaffin. A step of obtaining a middle distillate having a high proportion, and a step of mixing the obtained middle distillate and a light fraction of FT synthetic oil. In general, the fraction of FT synthetic oil increases in the content of isoparaffin contained in the distillate from light to heavy. For this reason, when a fuel base material is produced by fractionating a middle distillate from a cracked product obtained by hydrocracking a heavy fraction, the fuel produced from the middle distillate force of FT synthetic oil is simply used. Compared with the base material, the content of isoparaffin is high and a fuel base material is obtained. The fuel base material with a high content of isoparaffin and the low temperature fluidity is superior to the fuel base material with a low content of isoparaffin.

[0006] In the process of hydrocracking a heavy fraction of FT synthetic oil, in order to obtain a fuel substrate with a high isoparaffin content in a high yield, the heavy fraction is selectively converted into a middle fraction. It must be hydrocracked. Heavy distillate is excessively hydrocracked and a large amount of light distillates are produced.For example, if the selectivity for heavy distillate power is insufficient, it can be used as a fuel base. The yield of a fraction will fall. The present inventors have found that the middle fraction cannot be obtained from the heavy fraction in a sufficiently high yield by the method of hydrocracking the heavy fraction described in Patent Document 1.

[0007] Therefore, the present inventors examined a method for producing middle distillate from a heavy fraction with sufficiently high yield by hydrocracking. As a result, it was found that the middle distillate is produced with high selectivity as the reaction pressure for hydrocracking heavy fractions is lowered. The main reason for the formation of middle distillate with high selectivity by lowering the pressure is that heavy fraction, which is mainly liquid under the hydrocracking reaction conditions, maintains the contact efficiency with the hydrocracking catalyst, and hydrocracking. On the other hand, the decomposition products that have been hydrocracked and lightened are more likely to vaporize as the pressure decreases, and the contact efficiency of the cracked products with the hydrocracking catalyst decreases. This is thought to be due to the suppression of decomposition.

However, based on the above findings, hydrocracking of a heavy fraction at a low reaction pressure promotes deterioration of the hydrocracking catalyst and has a high conversion rate over a long period of time. It was difficult to continue.

[0009] The present invention has been made in view of such a situation, and in the process of hydrocracking a heavy fraction, the degradation of the hydrocracking catalyst can be sufficiently suppressed, and the middle fraction can be sufficiently reduced. It is an object of the present invention to provide a method for producing a fuel base material that can be produced with high selectivity.

Means for solving the problem

[0010] As a result of intensive studies to achieve the above object, the present inventors have produced a mixture by mixing a heavy fraction and a light fraction at a specific ratio, and the boiling point power contained in the mixture. The present inventors have found that the above problems can be solved by hydrocracking hydrocarbons exceeding ¾60 ° C under the condition that they are cracked at a specific cracking rate, and have completed the present invention.

[0011] That is, the method for producing a fuel base material of the present invention comprises a heavy fraction containing 90% by mass or more of hydrocarbon having a boiling point of more than 360 ° C and 95% of hydrocarbon having a boiling point of less than 150 ° C. % Of a light fraction containing at least 50% of the heavy fraction and 100 parts by weight of the heavy fraction so that the light fraction is 2 to 50 parts by weight, and in the presence of hydrogen and a hydrocracking catalyst, Hydrocracking process for hydrocracking the mixture obtained in the mixing process so that the cracking rate of hydrocarbons whose boiling point exceeds 360 ° C is 40 to 85% by mass, and cracking product obtained in the hydrocracking process And a separation step of separating a middle distillate containing 90% by mass or more of hydrocarbons having a boiling point of 150 ° C. or higher and 360 ° C. or lower from the product.

[0012] According to the present invention, a mixture in which a heavy fraction and a light fraction are mixed is hydrocracked. Thereby, a heavy fraction can be decomposed into a middle fraction with sufficiently high selectivity. For this reason, the middle fraction can be obtained from the heavy fraction with a high yield. The main reason why the middle distillate selectivity is sufficiently high is considered to be that the partial pressure of the cracked product is lowered, and the same effect as that obtained when the reaction pressure of hydrocracking is reduced is produced. Further, when the reaction pressure is lowered, there is a problem that deterioration of the hydrocracking catalyst is promoted mainly by carbon deposition on the surface of the hydrocracking catalyst. However, according to the present invention, the hydrocracking catalyst is sufficiently deteriorated. To be suppressed. The main reason for sufficiently suppressing the degradation of the hydrocracking catalyst is that the reaction pressure is not lowered, so that a sufficiently high reaction rate is maintained, and the carbon deposited on the hydrocracking catalyst surface can be sufficiently burned and removed. It is done.

[0013] Here, the decomposition rate of hydrocarbons having a boiling point exceeding 360 ° C means a decomposition rate defined by the following formula (1). In the following formula (1), “mass of hydrocarbons with boiling point over 360 ° C (before decomposition)” means hydrocarbons with boiling point over 360 ° C contained in the mixture subjected to hydrocracking process The mass of hydrocarbons whose boiling point exceeds 360 ° C (after decomposition) is the hydrocarbon whose boiling point contained in the decomposition product obtained by hydrocracking exceeds 360 ° C The quality of

[Number 1]

mv) Mass of hydrocarbons with boiling point over 36 ° C (before) Mass of hydrocarbons with boiling point over 3 6 trc (after decomposition) ( ₁₎ τ 'Mass of hydrocarbons with boiling point over 3 6 (before)

[0014] In the present invention, a material containing a wax obtained by Fischer-Tropsch synthesis (hereinafter referred to as "FT synthesis") can be used as the heavy fraction of the raw material. The wax obtained by FT synthesis is essentially free of environmentally hazardous substances such as sulfur and aromatic hydrocarbons. For this reason, when the heavy fraction of the raw material contains wax obtained by FT synthesis, a fuel base material in which the content of environmentally hazardous substances is sufficiently reduced can be produced. In addition, the FT synthetic oil wax has a high isoparaffin content. When hydrocracked, the middle distillate with a high isoparaffin content is compared to the middle distillate that is simply fractionated from the FT synthetic oil. can get. A middle distillate having a high isoparaffin content is a fuel base material having excellent low-temperature fluidity compared to a middle distillate having a low content. Here, the wax refers to a fraction containing 90% by mass or more of hydrocarbons having a boiling point exceeding 360 ° C.

[0015] In the present invention, as the light fraction used in the mixing step, those containing naphtha obtained by FT synthesis can be used. Naphtha obtained by FT synthesis is substantially free of environmentally hazardous substances such as sulfur and aromatic hydrocarbons. For this reason, if the light fraction used in the mixing step contains naphtha obtained by FT synthesis, a fuel base material with a sufficiently reduced content of environmentally hazardous substances can be produced. Here, naphtha means a fraction containing 95% by mass or more of hydrocarbons having boiling point S <150 ° C.

In the hydrocracking process of the present invention, the liquid space velocity is 0.3 to 3.51T ^{1 based on} the temperature 200 to 370 ° C., the pressure 1.0 to 5. OMPa, and the feed rate of the heavy fraction. It is preferable to hydrocrack the mixture under the following conditions. The hydrocracking catalyst contains 0.1 to 80.0% by mass of crystalline zeolite and amorphous metal oxide having heat resistance of 0.:! To 60.0% by mass based on the total amount of the support. And at least one metal selected from Group VIII metals of the Periodic Table of Elements of the carrier supported on this carrier in an amount of 0.:! To 3.0% by mass. Is preferred.

The invention's effect

[0017] According to the present invention, it is possible to sufficiently suppress degradation of the hydrocracking catalyst in the step of hydrocracking a heavy fraction, and to produce a middle fraction with sufficiently high selectivity. A method for producing a fuel substrate is provided.

Brief Description of Drawings

[0018] FIG. 1 is a diagram showing a configuration of a plant capable of implementing a method for producing a fuel base material according to the present invention.

Explanation of symbols

[0019] 10 · · · First distillation device, 20 · · Mixing device, 30 · · Hydrocracking device, 40 · · · Gas-liquid separation device, 5

0 ... Second distillation device.

BEST MODE FOR CARRYING OUT THE INVENTION

[0020] Hereinafter, preferred embodiments of the present invention will be described.

[0021] The heavy fraction of the raw material contains 90% by mass or more of hydrocarbons having a boiling point exceeding 360 ° C.

Examples of power and heavy fractions include heavy fractions obtained by distillation of FT synthetic oil and heavy fractions derived from petroleum.

[0022] The heavy fraction obtained by distillation of the FT synthetic oil is particularly suitable from the viewpoint of reducing the environmental load because it contains substantially no sulfur. A heavy, heavy fraction can be obtained by fractionating FT synthetic oil at atmospheric pressure and temperatures exceeding 360 ° C. FT synthetic oil contains various hydrocarbon compounds, but generally the paraffin component is the main component. The heavy fraction used in the present invention is not limited to those synthesized under specific FT synthesis conditions, but was fractionated from FT synthetic oil synthesized under synthesis conditions in which the content of isobaraffin component is high. It is preferable to use one. The use of a heavy fraction having an isoparaffin component content has the advantage that a fuel substrate with improved low-temperature fluidity can be produced.

[0023] Examples of heavy fractions derived from petroleum include heavy fractions obtained by refining and distilling petroleum. When using a heavy fraction derived from petroleum, it is preferable that the sulfur content of the heavy fraction is reduced to less than 1 mass ppm. [0024] In the mixing step, the light fraction is mixed with the heavy fraction of the raw material. The light fraction used in the mixing process contains 95% by mass or more of hydrocarbons having a boiling point of less than 150 ° C. Examples of strong light fractions include light fractions derived from FT synthetic oil, light fractions derived from petroleum, and saturated hydrocarbons with 9 or less carbon atoms. Among these, the light fraction derived from FT synthetic oil is particularly suitable from the viewpoint of reducing environmental impact because it contains substantially no sulfur.

[0025] Light fractions derived from FT synthetic oil include light fractions fractionated from FT synthetic oil under normal pressure and temperature conditions of less than 150 ° C, middle fraction or heavy fraction of FT synthetic oil. And refined oils containing hydrocarbons with a boiling point of less than 150 ° C obtained by hydrorefining and / or hydrocracking. Light fractions derived from petroleum include light fractions obtained by refining and distilling petroleum. When using a light fraction derived from petroleum, it is preferable that the sulfur content of the light fraction is reduced to less than 1 _{ppm by} mass. Examples of saturated hydrocarbons having 9 or less carbon atoms include methane, ethane, propane, butane, pentane, hexane, heptane, octane and nonane. Among these, one kind can be used alone, or two or more kinds can be mixed and used. The above saturated hydrocarbons preferably have 5 to 9 carbon atoms and are preferably liquid at normal temperature and pressure.

I like it. This is because it is easy to handle when it is liquid at room temperature and normal pressure.

A preferred embodiment of the plant used in the method for producing a fuel base material of the present invention will be described with reference to FIG. The fuel substrate production plant 100 shown in Fig. 1 includes a first distillation apparatus 10 for fractionating a heavy fraction from FT synthetic oil, and a heavy fraction and a light fraction fractionated by the first distillation apparatus 10. Are mixed with each other to obtain a mixture and hydrogen is added thereto, hydrocracking device 30 for hydrocracking the mixture, and cracked product transferred from the hydrocracking device 30. A gas-liquid separation device 40 that separates the separated liquid phase into a liquid phase and a second distillation device 50 that fractionates the separated liquid phase to obtain an intermediate fraction.

[0027] The first distillation apparatus 10 is an atmospheric distillation apparatus, and can fractionate FT synthetic oil into three fractions separated by boiling temperatures of 150 ° C and 360 ° C. The first distillation apparatus 10 is connected to a line 1 for introducing FT synthetic oil, and a line 12, a line 13 and a line 14 for transferring each fractioned fraction. Line 12, 13 and 14 are each , Light fractions fractionated at temperatures below 150 ° C, middle fractions fractionated at temperatures between 150 ° C and 360 ° C, and fractions at temperatures above 360 ° C It is a line for transferring heavy fractions.

[0028] The mixing device 20 is disposed downstream of the first distillation device 10. The mixing device 20 is a device for mixing each fluid supplied to the hydrogenation decomposition device 30. Various fluids introduced in the space inside the mixing device 20 are sufficiently mixed. That is, the mixing device 20 mixes a heavy fraction and a light fraction of FT synthetic oil at a predetermined mixing ratio to produce a mixture, and adds hydrogen at a predetermined mixing ratio to the heavy fraction. It can be configured. The mixing device 20 is connected to a line 14 for transferring a heavy fraction, a line 12a branched from a line 12 for transferring a light fraction, and a line 15 for introducing hydrogen. A line 21 connected to the mixing device 20 is a line for transferring the fluid to be treated containing the mixture and hydrogen to the hydrocracking device 30.

[0029] The hydrocracking apparatus 30 is a fixed-bed hydrocracking apparatus, in which a hydrocracking catalyst is arranged. The hydrocracking apparatus 30 is configured such that the fluid to be treated introduced from a line 21 connected to the top of the hydrocracking apparatus 30 flows from the upper side to the lower side of the catalyst layer in the hydrocracking apparatus 30. The hydrocracking apparatus 30 includes a heating means (not shown) that adjusts the temperature conditions of hydrocracking. Further, the hydrocracking apparatus 30 is provided with a back pressure valve 30a for adjusting the hydrocracking pressure condition at the downstream portion thereof. A line 32 connected to the hydrocracking apparatus 30 is a line for transferring the cracked product generated by the apparatus to the gas-liquid separator 40.

[0030] As the hydrocracking catalyst disposed in the hydrocracking apparatus 30, 0.1 to 80.0% by weight of crystalline zeolite and amorphous metal oxide having heat resistance 0.:! To 60.0% by weight Containing at least one metal selected from VIA metal and Group VIII metal of the Periodic Table of Elements carried on the carrier, and containing 0.:! To 3.0% by mass. Can be used

[0031] USY zeolite can be used as the crystalline zeolite. Here, “USY zeolite (ultra-stable Y-type zeolite, UltraStable Y_Zeolite)” means a product prepared by dealumination of Y-type zeolite by acid treatment or steam treatment. [0032] The molar ratio of silica / alumina in USY zeolite is not particularly limited, but is preferably 10 to 200, more preferably 15 to 100, and most preferably 20 to 60. If the molar ratio of silica / anolemina is less than 10, lightening of the heavy fraction tends to occur, and if it exceeds 200, the catalytic activity tends to be insufficient.

[0033] The average particle size of USY zeolite is preferably 1.0 μm or less, more preferably 0.

It is as follows. When the average particle size of USY zeolite exceeds 1. O zm, the heavy fraction tends to be lightened.

[0034] Further, the ratio of USY zeolite in the hydrocracking catalyst support is not particularly limited. From the viewpoint of suppressing lightening of the heavy fraction, the ratio of USY zeolite is 15% by mass based on the total amount of the support. 5% by mass or less is more preferable.

[0035] Among the components constituting the carrier of the hydrocracking catalyst, an amorphous metal oxide having heat resistance is used. Such an intangible metal oxide is a solid acid, and one or more selected from silica alumina, anoremina polya, silica zircoure, silica magnesia and silica titania are used. Among these solid acids, it is particularly preferable to use an alumina polya which preferably uses silica alumina, silica zirconia and alumina polya.

[0036] The hydrocracking catalyst used in the present invention may further contain a binder for molding a carrier. The binder is not particularly limited, but preferred binders include anoremina and silica. The shape of the carrier is not particularly limited, and may be a granular shape or a cylindrical shape (pellet).

[0037] On the carrier, one or more metals selected from Group VI A metals and Group VIII metals of the periodic table are supported. Specific examples of Group VI A metals include chromium, molybdenum, and tungsten. Specific examples of the Group VIII metal include cobalt, nickelo, rhodium, palladium, iridium, and platinum. Among these metals, it is more preferable to use one or more selected from nickel, palladium and platinum, preferably one or more selected from Group VIII metals of the Periodic Table. Examples of a method for supporting these metals on a carrier include a method in which an aqueous solution containing the above metal is impregnated in a carrier, followed by drying and firing. The supported amount of the metal in the hydrocracking catalyst is not particularly limited, but is usually 0.:! To 3.0% by mass with respect to the support. [0038] The gas-liquid separator 40 is provided downstream of the back pressure valve 30a, and is a device for separating the decomposition product into a gas phase and a liquid phase. The gas-liquid separator 40 is connected to a line 41 and a line 42 for transferring the separated gas phase and liquid phase, respectively.

[0039] The second distillation apparatus 50 is connected to a line 42 through which the liquid phase separated by the gas-liquid separation apparatus 40 is transferred. The second distillation apparatus 50 is an atmospheric distillation apparatus and can fractionate the liquid phase into three fractions separated by boiling temperatures of 150 ° C and 360 ° C. The second distillation apparatus 50 is provided with a line 52, a line 53, and a line 54 for transferring each fractionated fraction. Lines 52, 53, and 54 are a light fraction that is fractionated at temperatures below 150 ° C, an intermediate fraction that is fractionated at temperatures of 150 ° C to 360 ° C, and 360, respectively. It is a line for transporting heavy fractions that are fractionated at temperatures exceeding ° C. The line 52a for returning all or part of the light fraction transferred from the second distillation apparatus 50 to the upstream of the hydrocracking apparatus 30 may be branched from the line 52. In this case, the line 52a is preferably connected to the mixing device 20. Similarly, a line 54 a for returning all or a part of the heavy fraction to be transferred to the second distillation apparatus 50 force upstream of the hydrocracking apparatus 30 may be branched from the line 54. In this case, the line 54a is preferably connected to the mixing device 20.

[0040] Hereinafter, as a preferred embodiment of the method for producing a fuel substrate according to the present invention, a method for producing a fuel substrate using the plant 100 shown in Fig. 1 will be described. In Plant 100, a heavy fraction (wax) fractionated from the FT synthetic oil is used as the heavy fraction of the raw material, and a light fraction that is mixed with the heavy fraction in the mixing process is fractionated from the FT synthetic oil. Use light fractions (naphtha).

[0041] The FT synthetic oil is fractionated by the first distillation apparatus 10 into three fractions separated at a temperature of 150 ° C and a temperature of 360 ° C: a light fraction, a middle fraction and a heavy fraction. . The fractionated light fraction, middle fraction and heavy fraction are transferred from the first distillation apparatus 10 via line 12, line 14 and line 13, respectively.

[0042] The heavy fraction is introduced into the mixing device 20 via line 14. The light fraction is introduced into the mixing device 20 via the line 12a. A heavy fraction and a light fraction are mixed at a specific ratio to obtain a mixture (mixing step). The mixing ratio of heavy fraction to light fraction is The light fraction is 2 to 50 parts by mass with respect to 100 parts by mass. If the light fraction is less than 2 parts by mass with respect to 100 parts by mass of the heavy fraction, the effect of mixing the light fraction will be insufficient. descend. The mixing ratio is more preferably 10-35 parts by mass, preferably 5-40 parts by mass of light fractions with respect to 100 parts by mass of heavy fractions.

[0043] Hydrogen necessary for the hydrocracking reaction is introduced into the mixing apparatus 20 via the line 15 and added to the mixture. It is preferable that the amount of hydrogen added to 1 part by volume of the heavy fraction supplied to the hydrocracking unit 30 is 50 to 1000 parts by volume (standard state). 70 to 800 parts by volume (standard state) ) Is more preferable.

A fluid to be treated containing the mixture and hydrogen is introduced into the hydrocracking apparatus 30 via the line 21. The fluid to be treated flows through the hydrocracking catalyst layer in the hydrocracking apparatus 30 from the upper side to the lower side and is hydrocracked (hydrocracking step). At this time, the hydrocracking reaction conditions are adjusted so that the cracking rate of hydrocarbons whose boiling point in the fluid to be treated exceeds 360 ° C is maintained at a specific value. As the reaction conditions to be adjusted, it is preferable to adjust the reaction temperature from the viewpoint of easy adjustment.

[0045] The cracking rate of hydrocarbons having a boiling point exceeding 360 ° C in the hydrocracking process is 40 to 85% by mass, preferably 45 to 80% by mass, and 50 to 70% by mass. More preferably. If the decomposition rate is less than 40% by mass, the amount of decomposition products produced is small and the yield of middle distillate becomes insufficient. On the other hand, if it exceeds 85% by mass, the light fractions contained in the decomposition products are contained. The rate is high and the yield of middle distillate is insufficient.

[0046] As described above, in the hydrocracking step, the reaction conditions are adjusted so that the decomposition rate of hydrocarbons with boiling points exceeding 360 ° C is maintained at a specific value. The reaction conditions can be adjusted by monitoring the composition of the treatment composition. Specifically, the decomposition products transferred in line 32 are collected periodically, and the composition of the decomposition products is analyzed by composition analysis, such as by distillation gas chromatography. From this analysis result, the decomposition rate of hydrocarbons with boiling points over 360 ° C is calculated, and based on this result, the hydrocracking reaction conditions are adjusted.

[0047] The reaction temperature during the hydrocracking is generally a force of 180 to 400 ° C, preferably 200 to 370 ° C, more preferably 250 to 350 ° C. If the reaction temperature is less than 200 ° C, The decomposition reaction tends not to proceed sufficiently. On the other hand, when it exceeds 370 ° C, the yield of middle distillate tends to decrease or the decomposition products tend to be colored. When adjusting the reaction temperature in order to maintain the decomposition rate of hydrocarbons whose boiling point exceeds 360 ° C, the initial temperature at the start of operation of the hydrocracking device 30 should be, for example, about 315 ° C. Good.

[0048] The liquid hourly space velocity (LHSV) based on the amount of heavy fraction supplied to the hydrocracking unit 30 is generally a force of 0.1 to 10.01T ¹ , preferably 0.3 to 3. 51T is ¹ . The reaction pressure is usually 0.5 to: 12. OMPa, preferably 1.0 to 5. OMPa.

[0049] The decomposition product hydrocracked in the hydrocracking apparatus 30 is introduced into the gas-liquid separator 40 via the line 32. The gas-liquid separator 40 separates the decomposition products into a gas phase containing unreacted hydrogen gas or a hydrocarbon having a carbon number of 4 or less, and a liquid phase containing middle distillate and heavy distillate ( Separation step). The separated liquid phase is introduced into the second distillation apparatus 50 via the line 42.

[0050] The liquid phase is fractionated by the second distillation apparatus 50 into three fractions separated by boiling temperatures of 150 ° C and 360 ° C, namely a light fraction, a middle fraction and a heavy fraction ( Separation step). The middle distillate obtained here contains 90% by mass or more of hydrocarbons having a boiling point of 150 ° C or higher and 360 ° C or lower. Part or all of this middle distillate is used as a fuel substrate.

[0051] The light fraction transferred in the line 52 is returned to the mixing apparatus 20 via the line 52a, and can be used as a light fraction to be mixed with the heavy fraction in the mixing step. In addition, the heavy fraction transferred through the line 54 can be returned to the mixing device 20 via the line 54a and used as a heavy fraction of the raw material for hydrocracking.

As described above, the embodiments of the present invention have been described in detail, but various modifications are possible, not limited to the above embodiments. For example, the mixing of the heavy fraction and the light fraction is not necessarily performed by the mixing device 20, but is performed by injecting the light fraction into the line 14 where the heavy fraction is transferred. Moyore. In addition, the hydrogen necessary for the hydrocracking process only needs to coexist with the mixture in the hydrocracking process. Therefore, the addition of hydrogen can be performed at the same time as or before or after the mixing step as long as it is before the hydrocracking decomposition step.

[0053] As the hydrocracking apparatus used in the hydrocracking process, a fixed bed type is exemplified, but There is no particular limitation as long as it can contact the physical fluid with the hydrocracking catalyst. For example, a fluidized bed hydrocracking apparatus may be used.

[0054] The hydrocracked treatment composition is separated into a gas phase and a liquid phase by a gas-liquid separator, and these separations are performed using two or more gas-liquid separators having different temperature and pressure conditions. You may go. Further, the distillation pressure of the first and second distillation apparatuses is not necessarily normal pressure. The distillation pressure can be set so that the obtained fraction has desired distillation characteristics. In the second distillation apparatus, the middle distillate may be fractionated into two or more types. In this case, the light distillate may be the fuel base for kerosene, and the heavy distillate may be the fuel base for light oil. it can.

Example

[0055] Hereinafter, the present invention will be specifically described based on Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Example 1]

It consists of USY zeolite with an average particle size of 0.4 μΐη (silica / alumina molar ratio 37.0), silica alumina (silica / alumina molar ratio 14.0), and an alumina binder. : A carrier having a mass ratio of 40 (a cylindrical molded product having a diameter of about 1.6 mm and a length of 3 to 6 mm (average of about 4 mm)) was prepared. This carrier was impregnated with an aqueous solution of chloroplatinic acid, and 0.8% by mass of platinum was supported on the carrier mass. This was dried and calcined to obtain a hydrocracking catalyst.

[0057] Hydrocracking of a mixture containing wax and naphtha fractionated from FT synthetic oil was performed using a fixed bed hydrocracking apparatus. The reactor was filled with 150 ml of the above hydrocracking catalyst.

[0058] Wax obtained by fractionating FT synthetic oil with a boiling point exceeding 360 ° C, and naphtha obtained by fractionating FT synthetic oil with a boiling point of less than 150 ° C (isoparaffin content: less than 5% by mass) And a mixture to be supplied to a fixed bed hydrocracking apparatus was prepared. The mixing ratio was 20 parts by mass of naphtha per 100 parts by mass of wax.

[0059] The mixture was supplied from the top of the hydrocracking apparatus so that the supply rate of the wax contained in the mixture was 300 ml / h. In addition, hydrogen was supplied from the top of the hydrocracking apparatus so that the hydrogen oil ratio based on the supply amount of wax contained in the mixture was 680 NL / L. water The pressure conditions for hydrocracking were such that the inlet pressure of the hydrocracker was constant at 4. OMPa. The pressure was adjusted with a back pressure valve.

[0060] The initial temperature at the start of operation of the hydrocracking apparatus was 315 ° C. The temperature conditions of the hydrocracking unit were gradually increased to compensate for the decrease in activity due to degradation of the hydrocracking catalyst and to keep the wax cracking rate constant. When adjusting the temperature conditions, the hydrocracking power was analyzed by distillation gas chromatography for the distillation properties of the resulting decomposition products. Based on the analysis results, the temperature of the hydrocracking unit was adjusted so that the cracking rate of wax was 70% by mass.

[0061] Calculated by dividing the temperature increased over 10 days from the 10th day to the 20th day from the start of operation of the hydrocracking unit by 10, the reaction temperature increase averaged per day was reduced by the catalyst. It was defined as the conversion rate.

[0062] In the distillation gas chromatographic method described above, the middle distillate used as the fuel base material was separated from the decomposition product, and the distillation properties thereof were evaluated. At the same time, the distillation properties of a light fraction with a boiling point of less than 150 ° C and a heavy fraction with a boiling point of more than 360 ° C contained in the treatment composition were also evaluated. Table 1 shows the catalyst degradation rate and the mass ratio of the light fraction, middle fraction and heavy fraction measured by distillation gas chromatography. The mass fraction of light fractions shown in Table 1 is based on the value obtained by removing naphtha mixed with wax from the light fractions measured by distillation gas chromatography.

[0063] (Example 2)

A fuel base material was obtained under the same conditions as in Example 1 except that the mixing ratio of wax and naphtha was 3 parts by mass of naphtha with respect to 100 parts by mass of wax. Table 1 shows the catalyst degradation rate and the mass ratio of the light fraction, middle fraction and heavy fraction.

[0064] (Example 3)

A fuel base material was obtained under the same conditions as in Example 1 except that the mixing ratio of wax and naphtha was 38 parts by mass of naphtha with respect to 100 parts by mass of wax. Table 1 shows the catalyst degradation rate and the mass ratio of the light fraction, middle fraction and heavy fraction.

[Example 4]

Instead of naphtha produced by fractionating FT synthetic oil, the wax of FT synthetic oil is A fuel base material was obtained under the same conditions as in Example 1 except that naphtha (isoparaffin content: 80% by mass or more) produced by thawing was used. Table 2 shows the catalyst deterioration rate and the mass ratio of the light fraction, middle fraction and heavy fraction.

[0066] (Example 5)

A fuel base material was obtained under the same conditions as in Example 1 except that normal heptane was used instead of naphtha produced by fractional distillation of FT synthetic oil. Table 2 shows the catalyst degradation rate and the mass ratio of the light fraction, middle fraction and heavy fraction.

[0067] (Example 6)

The same conditions as in Example 1 except that desulfurized naphtha obtained from crude oil (sulfur yellow content: 0.8 mass ppm) was used instead of naphtha produced by fractionating FT synthetic oil. A fuel substrate was obtained. Table 2 shows the catalyst degradation rate and the mass ratio of the light fraction, middle fraction and heavy fraction.

[0068] (Comparative Example 1)

A fuel base material was obtained under the same conditions as in Example 1 except that the FT synthetic oil wax was not mixed with naphtha and only the wax was supplied to the hydrocracking apparatus. Table 3 shows the catalyst degradation rate and the mass ratio of the light fraction, middle fraction and heavy fraction.

[0069] (Comparative Example 2)

A fuel base material was obtained under the same conditions as in Comparative Example 1 except that the pressure condition of the hydrocracking apparatus was 3. OMPa. Table 3 shows the catalyst degradation rate and the mass ratio of the light fraction, middle fraction, and heavy fraction.

[0070] (Comparative Example 3)

A fuel base material was obtained under the same conditions as in Comparative Example 1 except that the pressure condition of the hydrocracking apparatus was 2. OMPa. Table 3 shows the catalyst degradation rate and the mass ratio of the light fraction, middle fraction, and heavy fraction.

[0071] [Table 1] Examples Examples Examples Examples

one two Three

AX

20 3 38

Mixing amount of naphtha, part by mass

Naphtha used in the process of mixing FT synthetic oil with FT synthetic oil

Light fraction Light fraction Light fraction Light fraction Hydrocracking pressure conditions, M P a 4.0 0 4.0 0 4.0

Decomposition rate of wax, mass% 70 70 70

Mass ratio of light fraction, mass% 9 1 4 7

Middle fraction mass ratio, mass ¾ 61 56 63

Mass fraction of heavy fraction. Mass ¾ 30 30 30

Catalyst degradation rate, ¾ / day 0. 042 0. 043 0. 041

[0072] [Table 2]

[0073] [Table 3]

Industrial applicability

The method for hydrocracking a wax and the method for producing a fuel substrate according to the present invention comprises: When bottom recycling is performed, it is possible to simultaneously improve the yield of middle distillate, which is the target of hydrocracking, and reduce the content of normal paraffin in the middle distillate. It is useful in producing a gentle clean liquid fuel.

Claims

The scope of the claims

[1] Heavy fraction containing 90% by mass or more of hydrocarbons with boiling point over 360 ° C and boiling point of 150

A mixing step of mixing a light fraction containing 95% by mass or more of a hydrocarbon having a temperature of less than ° C such that the light fraction is 2 to 50 parts by mass with respect to 100 parts by mass of the heavy fraction;

Hydrogenation which hydrocracks the mixture obtained in the mixing step in the presence of hydrogen and a hydrocracking catalyst so that the cracking rate of hydrocarbons whose boiling point exceeds 360 ° C is 40 to 85% by mass Decomposition process,

A separation step of separating a middle distillate containing 90% by mass or more of a hydrocarbon having a boiling point of 150 ° C or higher and 360 ° C or lower from the decomposition product obtained in the hydrocracking step;

A method for producing a fuel substrate, comprising:

[2] The method for producing a fuel substrate according to claim 1, wherein the heavy fraction contains a wax obtained by Fischer-Tropsch synthesis.

[3] The method for producing a fuel substrate according to claim 1 or 2, wherein the light fraction contains naphtha obtained by Fischer-Tropsch synthesis.

[4] In the hydrocracking step, a temperature of 200 to 370 ° C, a pressure of 1.0 to 5.0 MPa, and a liquid space velocity of 0.3 to 3.51T ^{1 based} on the supply amount of the heavy fraction. The method for producing a fuel base according to any one of claims 1 to 3, wherein the mixture is hydrocracked under conditions.

[5] The hydrocracking catalyst contains 0.:! To 80.0% by mass of crystalline zeolite and 0.:! To 60.0% by mass of amorphous metal based on the total amount of the support. A carrier containing an oxide, and one or more metals selected from Group VIII metals of element periodic table of 0.:! To 3.0% by mass with respect to the carrier, supported on the carrier. The method for producing a fuel base material according to any one of claims 1 to 4, wherein the fuel base material is produced.